When I was working on my MS thesis at Northern Arizona University on aetosaurs, I was struck by the announced discovery of fossil "reptile nests" (Hasiotis and Martin, 1999) and the earliest records of many social insect nests including bees (e.g., Hasiotis et al., 1998). It seemed possible that aetosaurs could have been the nest maker, and evidence from the site had also suggested some degree of parental care from whomever the nest maker was. Likewise, I had been tossing around the idea of possible alternative food sources for aetosaurs and insects might just fit the bill, especially if there was evidence for social insect nests during the Late Triassic. This early bee record also suggested that bees evolved before and separately from angiosperms.

Photograph of purported reptile nests from Petrified Forest National Park. From Hasiotis and Martin, 1999.

When I started working at the park one of the first sites my supervisor took me to was the site of these "reptile nests" as she was curious what another geologist/paleontologist would think of them. Needless to say I was extremely disappointed. Every geologist I have showed them to since agrees with my assessment, they are simply erosional potholes in a sandstone. Visiting the site provides the detailed evidence for this determination. Unfortunately this discovery resulted in much popular press and these "nests" even make into more recent research papers; however, no detailed rebuttal has yet been published. Other nests attributed to aetosaurs have been described from the Triassic of Italy (Avanzini et al., 2007), but I have not been able to see these first hand to evaluate them.

[Note: I had forgotten about the rebuttal on the Petrified Forest 'nests' by Lucas and Hunt (2006)].

The bee's nest record, from a log in the Petrified Forest, was immediately criticized by entomologists (e.g., Grimaldi, 1999; Engel, 2001), arguing that these traces provide no signature evidence of bee activity. Unlike the "reptile nests"; however, these must have been made by some type of organism, and beetles have been the most cited tracemaker. Also unlike the 'reptile nests' there is a detailed rebuttal paper that provides good evidence that these traces are not bee's nests, but rather represent a new form of beetle trace (Lucas et al., 2010 - see abstract below). Like the 'reptile nests' every person with an entomological background that I have shown these to agrees with this assessment and like the 'reptile nests' these story too received much popular press before a paper was published.

The lesson here is that we should avoid oversensationalizing 'amazing' discoveries like these until peer reviewed papers describing them in detail are published in the relevant literature. Failing to do so can cause long term misunderstandings regarding our fossil resources. This also happened in the case of Chindesaurus bryansmalli ("Gertie") which was hailed as the world's "earliest" dinosaur, a claim which still makes it in to occasional brochures and webpages about Petrified Forest National Park.

It can be very tempting to get excited about the finds and want to make a big media splash, but in the end they cannot be considered valid or relevant until they pass the critical test of peer review. As I argued in a previous post, having these papers reviewed by qualified entomologists and geological colleagues can help avoid having your work criticized and/or not accepted by future workers.

Having seen the specimens I believe that the Lucas et al's. interpretation has much merit; as do several other entomologists; however, it would appear that the debate is not entirely closed. I do especially have to agree with the last quote in this news story. I'd like to see more evidence for such a sensational claim.

Abstract - Published records of supposed Triassic bees' nests are based on trace fossils in silicified wood and in sandstone in Upper Triassic strata of the Chinle Group in Petrified Forest National Park, Arizona. A critical, firsthand restudy of these trace fossils indicates that they lack diagnostic features of bees' nests, such as cells with smooth linings and spiral closure caps. Indeed, many of the observations claimed to identify these traces as bees' nests cannot be replicated. Instead, the putative Triassic bees' nests can be classified as: 1. Clavate borings in petrified wood, somewhat similar to Teredolites; these borings preferentially penetrate
heart-rot fungus (Polyporites) and are mostly likely larval chambers of wood-boring beetles. 2. Cylindrical,
vertical burrows in sandstone assignable to Skolithos; these are almost certainly arthropod produced. The
recognition that the Chinle Group trace fossils are not bees' nests eliminates them as evidence that decouples
bee origins from the Cretaceous origin of angiosperms. The Triassic trace fossils in silicified wood are also a
new and unique record of likely beetle borings in Triassic wood.

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About Me

My name is Bill Parker and I am a paleontologist in northeastern Arizona. While my day job mainly involves roaming the badlands of Petrified Forest National Park picking up bit after bit of phytosaur scrap (and finding some good stuff in-between), thus my main focus is the paleontology of the Triassic Period. However, I also have a very strong interest in Civil War history, and am a direct descendent of veterans who fought on both sides. Note: This is a personal site and all posts are my own opinions and do not represent the opinions of the National Park Service.